“I’ll see you on the dark side of the Moon” Pink Floyd sang in the band’s signature 1973 hit.
And China has done exactly that with the touchdown of its Chang-e 4 lander and Yutu 2 rover on the dark side of the Moon.
Chang’e 4 will make astronomical observations and probe the composition of the soil, not unlike the latest Mars probe.
Until now all lunar missions have landed on the side of the Moon that faces the Earth.
With the lunar mass spinning on its axis at the same rate as it orbits the earth, once every 28 days, it’s made sense so far to have all landings on “the near side”.
The Chang-e 4 probe landed at 10:26am on January 3 and, shortly after, beamed confirmation via a lunar orbit relay satellite.
Pictures in both monochrome and colour show the probe had landed in an area that appeared smooth surfaced and devoid of any real features.
The location, the South Pole-Aitken Basin, is also thought to be one of the lunar surface’s oldest impact zones, with estimates of between 3.9 to 4.4 billion years of age.
The landing is “a big deal” because it used an engineering technique that saw the spacecraft itself chose a safe place to touch down in treacherous terrain — something called “autonomous hazard avoidance”.
Purdue University lunar and planetary scientist Jay Melosh recalls mentioning the idea of an unfunded NASA lunar mission about eight years ago, only to be told it wasn’t doable at the time.
“The Moon is more challenging to land on than Mars,” Melosh said. “On Mars, you can pick out smooth areas.”
There is another astronomical possibility, with the far side of the Moon effectively shielded from the radio noise earth generates.
“The far side of the Moon is a rare, quiet place that is free from interference from radio signals from Earth,” mission spokesman Yu Guobin said, according to the official Xinhua News Agency.
“This probe can fill the gap of low-frequency observation in radio astronomy and will provide important information for studying the origin of stars and nebula evolution.”
Harvard astronomer Avi Loeb said that in future, it may be possible to see much further — and thus earlier — into the universe from the far side because the Moon itself will block interfering radio signals from Earth.
From the far side, scientists may eventually be able to peer back 50 million to 100 million years after the Big Bang, when the first stars were born — or even earlier, he said.
Chang-e 4 is just the second probe to have made the lunar journey since 1976, with the last landing the Chang-e 3 probe in 2013.
It’s not known if China included a copy of the Pink Floyd album with the probe and rover.
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